SDRAM 64Mb H-die (x4, x8, x16) CMOS SDRAM
Rev. 1.4 November 2003
SIMPLIFIED TRUTH TABLE (V=V alid, X=Don′t care, H=Logic high, L=Logic low)
Command CKEn-1 CKEn CS RAS CAS WE DQM BA0,1 A10/AP A11,
A9 ~ A0Note
Register Mode register set H X L L L L X OP code 1,2
Refresh
Auto refresh HHLL LHX X 3
Self
refresh
Entry L 3
Exit L H LHHHXX3
HX XX 3
Bank active & row addr. H X L L H H X V Row address
Read &
column address Auto precharge disable HXLHLHXVLColumn
address
(A0 ~ A9)
4
Auto precharge enable H 4,5
Write &
column address Auto precharge disable HXLHLLXVLColumn
address
(A0 ~ A9)
4
Auto precharge enable H 4,5
Burst stop H X L H H L X X 6
Precharge Bank selection HXLLHLX
VL X
All banks XH
Clock suspend or
active power down Entry H L HX XXXXLVVV
Exit L H X X X X X
Precharge power down mode Entry H L HX XXXX
LHHH
Exit L H HX XXX
LVVV
DQM H X V X 7
No operation command H X HX XXXX
LHHH
1. OP Code : Operand code
A0 ~ A11 & BA0 ~ BA1 : Program keys. (@ MRS)
2. MRS can be issued only at all banks precharge state.
A new command can be issued after 2 CLK cycles of MRS.
3. Auto refresh functions are as same as CBR refresh of DRAM.
The automatical precharge without row precharge command is meant by "Auto".
Auto/self refresh can be issued only at all banks precharge state.
4. BA0 ~ BA1 : Bank select addresses.
If both BA0 and BA1 are "Low" at read, write, row active and precharge, bank A is selected.
If both BA0 is "Low" and BA1 is "High" at read, write, row active and precharge, bank B is selected.
If both BA0 is "High" and BA1 is "Low" at read, write, row active and precharge, bank C is selected.
If both BA0 and BA1 are "High" at read, write, row active and precharge, bank D is selected.
If A10/AP is "High" at row precharge, BA0 and BA1 is ignored and all banks are selected.
5. During burst read or write with auto precharge, new read/write command can not be issued.
Another bank read/write command can be issued after the end of burst.
New row active of the associated bank can be issued at tRP after the end of burst.
6. Burst stop command is valid at every burst length.
7. DQM sampled at positive going edge of a CLK and masks the data-in at the very CLK (Write DQM latency is 0),
but makes Hi-Z state the data- out of 2 CLK cycles after. (Read DQM latency is 2)
Notes :